Method of and means for measuring porosity



sept. 14, 1926. 1,599,964

G. B. HAVEN l METHOD OF AND MEANS FOR MEASURING POROSITY Filed Jan. 9, 1926 :Patented sept. `14,` 192e.

N UNITED STATES GEORGE, B. HAVEN',` OE

PATENT OFFICE.

imTHoD or Manus Fon MnasunING PonosIrY.

Applicationl led January 9, 1926. Serial No. 80,835..

As is known, many fabrics and other substances de end for their usefulness on their ability either to restrain or to permit the -passage of gases or liquids through them.

As a result, the measurement of the quality of porosity is of considerable importance.

` The object ofvmy invention is toprovide an improved method of and means for measuring the porosity of a substance, such as a fabric, for example, and for a consideration of what I believe to be novel, and m invention, attention is directed to the following description and the claims-appended thereto. f v

In the drawing, Fig. 1 is a side elevation, partly in section, of a machine embodying l my invention and by the use of which my improved method may' be carried out.; Fig. 2

isa detail sectional view of certain of the parts shown in Fig. 1; Fig. 3 is a sectional lplan view taken on line 3-3,\ Fig.` 2; Fig.

'4 is a detail view, partly in section, of a form of blower which may be utilized in carryin out my invention', and Fig. 5 is a detai perspective view, partly broken away, of certain parts v I have found that the passage of afluid, in the form either of a liquid or a gas, through the interstices'ofa substance such as a heavy fabric for example, is a direct function of the similar passage of atmos`I pheric air through such substance. It follows, therefore, that by measuring the resistance which a substance offers to .the pas` sage of airthrough it, I can'measure and determine its porosity in suitable terms.

i According to `my improved method, I measure the resistance which the substance oers to the passage of air through it by .40 measuring the pressure required to effect the continuous ow of a uniform measuredwolume of air. through a unit area or vde nite area of the substance. I have found that the pressure s'o required is a direct function of '45 the porosity of the substance and forms -a measure of its porosity. Or, otherwise expressed, Ihave found that with the quantity of air passing through the fabric kept constant in amount, the porosity was directly related ,by a fixed law to the pressure building up upon the face of the fabric` where the air started to pass through it. Any Isuitable means may be employed in carrying 'out my improved method. One

4 surrounded f vided with a fiat surface such means, and an arrangement I now prefer is illustrated in the drawin Referring tothe drawing, 1 in icates a ase comprising a top 'wall 2 and supporting legs 3. v In top wall 2 is a circular opening by a raised finished surface 5. 6 lndlcates a frame which is U- sha ed and comprises two arms, an vupper arm and a lower arm 8. Lower arm 8 is provided with a circular base 9 which rests on finishedfsury facel5 and has a circular. centering projecf tion 10 which projects down into opening 4.

NEEDHAM, MASSACHUSETTS, ASSIGNOR TO FELT GOM- i PANY, .'A CORPORATION 01."v NEW YORK.

Frame 6 is attached to top wall 2'by a suitable number of bolts 11 which extend through base 9 and through a plate 12 located beneath top wall 2. When the nuts of the wall surrounding o ening 4 `1's clamped between surface 5 an the opposed surface on plate 12. This serves to clamp frame 6 vto base 1. As will be clear, by loosening the nuts on bolts v41-1, frame 6 may be tiirned on its vertical axis relatively't'o base 1 to any desired position, and it may be fastened in the desired position by tightening the nuts again. o

The forward end of upper arm 7 is pro- 13 to which is fas'- tened a yoke comprising a base` 14 and spaced arms 15. In the present instance base 14 is shown as being provided with a recess 16 in which the forward end of .arm Y 7 fits and as being fastened to it by studs 17.

on top of boltsv 11 are tightened,'the edge However, any suitable' fastening arrangement may be used. The opposed surfaces of arms 15 are provided with raised sur`- faces 18 from which project bearing pins 19, and mounted on pins 191s a gimbal ring '20. Gimbal ring 20 is provided with op# posed raised surfaces 21 from which project pivot pins 22, yand pivotally mounted on pins 22 is a sleeve 23, the lower end of which 1s provided with a flange 24. ARigidly fixed in sleeve 23. in any suitable manner 1s a tube 25. The lower end o f tube 25 is sbstantially `Hush with thelower end of sleeve 23 and is open. The upper end of tube 25 is closed by a tight itting'cover 26. With4 theabove descri ed arrangement, it will be vseen that tube 25 and anged sleeve23 form,

in substance, a unitary structure or conduit which 'is mounted between arms 15 on a. gimbal or universal joint. To maintain tn be 25 normally vertical but 'still pernnt of its moving on `its gimbal mounting, .it is connected to upper arm 7 by means of a spring 27 of suitable stiinessf One end of spring 27 is fastened in an eye on tube 25 and the other end is adjustably connected to a small bracket 28 on the arm. lThe stin s's of spring 27 is such that normally it hol s tube 25 stationary in vertical position but permits of thetube moving on its universal mounting in any direction when pressure is applied to a side ofthe tube.

The forward end of, lower arm 8 is provided with a flat surface to which 'a bracket l 28 is fastened in any suitable manner, such as by means of the bolts 29. Formed integral with bracket 28 and rigidly supported by it is a cylinder st-ructure comprising an upper cylinder 30 of .suitable diameter and a lower cylinder 31 of a diameter somewhat less than the diameter of cylinder 30. Attached to the lower end of lower c linder 31 is a tubular spring guard or shielyd 32. In

upper cylinder 30 is a sleeve 33 havinga flange 34'on its outer end. Fixed in sleeve 33 in any -desired or suitable manner is a tube 35, the u per end of which is flush with the upper en of the sleeve. Tube 35 projects down through lower cylinder 31 and its lower end beginning at a point somewhat below the lower end of sleeve 33 is enlarged in outside diameter by increasing the-thickness of its wall, so that it fits lower cylinder 31. There is thus provided an annular cylindrical chamber 36 between upper cylinder 30 and lower cylinder 31.

' Connected to chamber 36 is a pipe 37 which at its other end is connected to a source of fiud under pressure. For example,

it may -connectto a suitable source of air pressure; Connected to pipe 37 is a pressure gauge 38 and arranged in pipe 37 is a three way control valve 39 and a suitable pressure re u cing valve 40. Valve 39 is arranged so that in4 one`position it connects chamber 36 to the air pressure supply and in another position it disconnects it from the air presy sure supply and connects it to a region of lower pressure, such as to atmosphere. Sleeve 33 and tube 35 are provided with suitable packing rings 41 to prevent leakage from cham r 36. Surroundmg the lower end' of tube 35 is a spring 42 arranged between the lower end of 'cylinder 3l and a collar 43 threaded onto the lower end of'tube 35.

This s ring serves to normally hold sleeve 33 and tu 35-in their lowermost position with fiange 34 in engagement with the top of c 1- inder, 30. Sleeve 33 and tube 35 are rigidly fastened together and form in substance a unitary e'lindrical piston which moves in the cylin er structure comprising cylinders 30 and 31. f

'Tube 25 with iange 24 atlits lower end and I* tube 35 with iiange 34 at its upper en'd stand in vertical alignment with each other Iand ured. In Fig. 2, this substance is indicated at A. When a substance, such as the substance A, iseclamped between anges 24 and 34, as is shown 1n Fig. 2, tubes 25 and 35 form a continuous 'conduit o en at its lower end and across which conduit the substance A extends at a point intermediate between the two ends of the conduit. This forms an arrangement whereby a definite area of substance A may be subjected to air pressure to effect passage of air through it.

Connected to the upper end of tube 25 is a means whereby a definite measured volume of air may be supplied continuously to tube 25. Any suitable means may be utilized for this purpose. Preferably I employ a suitable air pump or air blower and regu.- late it so that it supplies continuously a constant volume. of air to tube 25 irrespective of the pressure in the tube. 44 indicates a rotary blower which may be mounted in any suitable manner and driven by any suitable means. In the present instance, it is shown as being mounted directly on top of frame 6l adjacent to its forward end and as being driven by an electric motor 45 which isconnected to itby a belt 46. Motor 45 may be mounted adjacent to blower 44 in any convenient manner. It is shown in -the present instance as being located above it. This arrangement, however, is only by way of example, and for illustrative purposes. The blower and motor may be arranged advantageously side by side on top of the frame arm 7.

Blower 44 is provided with an inlet conduit 47 which communicates with the atmoshere and with a discharge conduit 48 which 1s connected by a pipe 49 to the top of tube 25. Communicating with discharge conduit 48 is a by-pass conduit or waste passage 50 which is controlled 'by an outwardly opening pressure relief valve 5l which is biased toward a seat 52 by a spring 53. Spring 53 ma be adjusted by means of a member 54 wh1ch threads into an opening in the blower casing. The inner end of' member 54 engages spring 53 and the outer end is provided with a knurled head 55 for use in turning the member. By adjusting spring 53, the pressure at which valve 51 opens may be regulated. a waste pipe 56. j In tube 25 adjacent to itsupper end is arranged a pressure difference creating device wh1ch creates a fessure difference which bears a definite re ation to the rate of flow of fluid through the tube. ."In the present instance, this device is in the form of a plate 57 having an orifice 58 in it, this being a in U-tube 59,

orifice plate 57. It is shown as comprising a U- tube 59 having one leg connected to tube above orifice plate 57 by a pipe 60 and its other leg connected to tube 25 below orilice plate 57 by a pipe 61. Pipe 60 forms the leading pressure. connection and pipe 6l uid B. indicating The upper ends ofthecolumns o with a suitable scale plate liquid cooperate 62 for indicating the deflection of the liquid in the U-tube.v

When fluid How takes v duit 25, there is a drop in pressure across The 4drop across the orifice plate is measured by lthe deflection of the liquid" in U-tube 59. It follows, therefore, that if blower 44 is regulatedl to maintain a constant deflection ofthe liquid constant volume of liow through tube 25,

' since .there will regulating the lating a suitable valve 49a gauge 63 and a recording which are connected to tu e 25 in multiple V standsin the position i sure and to"conneotaniiular cylinder 36to .y atmosphere, 4and spring 1n A. IJ-tube 59 and suitable distance whichl serve to secure-uniformity of flowA speed of motor.45, by reguin discharge pipe 49, or in any suitable manner.

Connected to tube is suitable means pressure obtaining in this portion of the tube In the present instance, this means is shown as comprising an inclined pressure by a pipe 65. 66 and 67 in connecting the them from tu are valves for use gauges to and disconnectpurposse of illustration. l practice, ese instruments may be and preferably are mounted directlyron frame 6in any suitable manner.

. In `pipes 47,' 49 and 56 are arranged suitfro'm it are bale screens 69 across the entire areaoftube'25.

'When the machine is not in use, to shut oli the valve 39 air pres- /42 holds. flange 34 top -lo'ffcylin i will take be a constant drop in presi 25 adjacent to its lower able screens 68 for preventing foreign matp 24 and 34 and valve 39 turned to admit compressed .air to annular cylinder 36. This raises the piston structure comprising sleeve 33 and tube l35 and clamps material A between langes 24 wand 34, as is shown in Fig.

of air blower tube 25, through material A, and out at the bottom of tube 35.

is being supplied continuously by material A requires e pressure must exist in advance of themateria the predetermined constant volume of airwill be forced to through orifice 58 and pressure in advance (Lf porosity determination has been made, valve 39 is turned to relieve the pressure in annular cylinder 36 whereupon and is turned on until the material v desired'constant volume 44 to tube 25. This-air flows down flow continuously material A. Thev spring 42 forces sleeve 33 and tube 3 5 down- In the use of the machine, the4 material, the /porosity of which is to be determined, may be sometimes of uneven and varying thickness. By providing a universal mounting for tube 25 and by holding it yieldingly In this connection, various connections ible such as rubber tubing, sothat the connections will not 'interfere with movements'o'f to tube 25 are made flex.-

the tube` 25-on its universal mounting. l

The machine is -especially well adapted for by the use of suitable'llexible material measuring the 'porosity o-ta fabric and in hown.l In the the machine frame an portion up tothe Whole width of the fa ric may be accommodated while taking porosity measurements at frequent intervals across the width.

Since frame 6 of the machine is swiveled on base 1, it may be turned to receive fabric from various positions. This .is of great convenience inthe use of the machine. The arrangement is such that frame 6 may be turned on base l throughout a complete revolution.

By my improved method, I am enabled to measure accurately the porosity of a material, such as a fabric; and by the use of my improved machine, the method may be carried out quickly and easily and with the required degree of accuracy.

In accordance-with the provisions of the patent statutes, I have described my improved method and the principle of opera.- tion of my invention, togetherwith the apparatus which I now consider to represent the best embodiment thereof, but I desire to ave it understood that the apparatus shown 1s only illustrative and that the invention may be Vcarried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is

' ity of a substance,

I 1. The method of measuring the 'porosity of'a substance which comprises measuring the pressure required to maintain a constant rate of flow of air through afdefinite area of the substance.

2. The method of measuring the porosity of a substance which comprises segregating a definite area of the substance and measuring the pressure required to maintain a constant rate ofl flow of air through such area. 3. In a machine for measuring theI porosity of a substance, the combination of means for segregating a definite area of the substance, means for maintaining a' constantrate of flow of air through such segregated area, and means for measuring the pressure required to eiiect such iow.' 4. In a machine for measuring the porosity of a substance, the combination of a conduit, means for clam ing a substance across the conduit, means or maintaining in the conduit a constant rate of flow of air, and means for measuring the pressure required to maintain such` constant rate of flow, of air throughthe'substance. y

-5. In a machine for measuring the poros the combination of a conduithavinga ilan e at one end, ,a second conduit having a fange at one end, means for moving said conduits toward each other to clamp a substance between said Han es, means for maintaining a constant rate of ow means associated connected y regulating said pump,

duit, means assoclated with the conduit for measuring the volume of air fiowing through the conduit, means for regulating the air supplying means to maintain constant the volume of air supplied to the conduit per unit of time, and means whereby a substance,

glie porosity of which is to be determined,

ay be clamped across said conduit.

7 In a porosity measuring machine, a U-shaped frame comprising two arms, conduits carried by said arms, means whereby .a substance may be clamped between adjacent ends of said conduits, means. for maintaining a constant rate of flow of air through said conduits, pressure in the conduits in the region 1n advance .of said clamping means. y

8. In a porosity measuring' machine, .a U-shaped frame comprising` two arms, a conduit connected to one of said arms by auniversal joint, a conduit connected to the other arm, said conduits being in. alignment, means for moving the second named conduit toward the lirst named conduit, whereby a substance may be clamped 'between them, with said conduits for maintaining a constant rate of flow of air through the conduits, and pressure measuring means connected to said first named conduit.

9. In a porosity measuring machine, the combination of a base, a U-shaped frame to the base by a swivel connection, conduits carried by said whereby a substance may tweengsaid conduits, pressure required to force a constant volume of air per unit of time through said conduits may be measured.

10. In a porosity measuring machine, the combination'of a conduit, an orifice plate in the conduit, means for measuring the ydrop in pressure across said oriiice, a pump for supplying air to said conduit, means for means for clamping a substance, the porosity owhich is to be measured, across the-end of said conduit, andv means for measuring the pressure in the conduit adjacent to the end over which the substance is adapted .to be clamped.

be vclamped be- In witness w my hand and seal this 31 day ofDec., 1925.

GEORGE B. HAVEN.

and means for measuring theV frame, means and means whereby the ius hereof, I have hereunto set 

